Tracy Chevalier's 1999 masterpiece, Girl with a Pearl Earring, was a tour de force, revealing the painter Vermeer through the eyes of his 16-year-old maid. A publishing sensation, the novel set the pattern for Chevalier's subsequent work: meticulously researched historical fiction, filled with gritty detail yet rendered in luminous prose.

An American, Chevalier has lived in London for decades, and her first six books are all set in Europe. But her seventh novel, The Last Runaway, crosses the Atlantic along with her English protagonist, a young Quaker named Honor Bright.

The year is 1850, and Honor has just been jilted by her fiance, so she decides to join her sister Grace, who is emigrating to Ohio. Grace is engaged to marry Adam Cox, a fellow English Quaker who has opened a dry goods store in Oberlin, a small but flourishing Quaker community.

But the sisters' plans go awry. On the overland journey to Ohio, Grace dies of yellow fever; a grieving Honor buries her sister en route. Honor finally arrives at the home of her intended brother-in-law, but their unorthodox living arrangement soon raises consternation among her co-religionists. Bowing to social pressure, Honor quickly marries Jack Haymaker, a local farmer, and begins a life under the iron rule of her mother-in-law, Judith, a Quaker elder.

Ohio in 1850 was a sparsely settled frontier. The reader experiences this uncouth New World through Honor's shocked English eyes. Women drink whiskey and shoot snakes; men spit tobacco in the street. Most troubling of all is the reality of slavery. Ohio isn't a slave state, but it serves as a major route in the Underground Railroad, and runaways regularly cross the Haymakers' property. The Haymakers refuse to offer them food or shelter, or to hide them when the local slave hunter comes to track them down — behavior that horrifies Honor.

From its very inception, the Society of Friends championed human equality and opposed slavery. In both America and England, Quakers were key figures in the abolitionist movement. But if the Haymakers helped runaways, they could be imprisoned and lose their farm. As Honor discovers, it's one thing to profess moral ideals and quite another thing to live by them.

Unlike the Haymakers, Honor can't look away from the plight of enslaved African-Americans. She decides to act.

Up until this point, Honor has been like a parcel, transported from one location to the next. But now her American adventure finally begins. Behind her husband's back, she becomes part of the Underground Railroad. When her family uncovers her secret, they give her an ultimatum: Either she stops helping escapees, or she'll be shunned from the community. By this time, Honor is heavily pregnant and her options seem to be running out. Will she be forced to join the ranks of runaways?

For a novel exploring such explosive themes, The Last Runaway is a quiet, contemplative read, mirroring the demeanor of its Quaker heroine. It might be too quiet for some readers. Much of the narrative is devoted to lengthy descriptions of Honor quilting and performing other homely domestic tasks. These scenes can become rather ponderous.

But I was deeply moved by Chevalier's evocations of how Honor's spirituality drives her every choice. According to Quaker belief, a divine inner light resides within every human being, no matter how bad they might seem on the outside. Viewing the characters through Honor's eyes, the reader catches flashes of light even in the slave hunter, Donovan, whose infatuation with Honor seems to bring him to the brink of reform. The runaways also come vividly to life as human beings filled with warmth and complexity. I only wish Chevalier had breathed more life into Honor's husband and mother-in-law, who seem flat and wooden.

Still, The Last Runaway is beautifully written and offers much for the reader to savor. Honor's story serves as a powerful testament to the force of conscience and the difference that just one inspired individual can make.

Mary Sharratt lives in Lancashire, England. Her most recent book is Illuminations: A Novel of Hildegard von Bingen.

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